Study of MT-302 in Adults With Advanced or Metastatic Epithelial Tumors

Prior treatment

• Known active CNS metastasis and/or carcinomatous meningitis. Participants with previously treated brain metastases may participate provided they are radiologically stable, (ie, without evidence of progression for at least 4 weeks by repeat imaging), clinically stable, and without requirement of steroid treatment for at least 14 days prior to the first dose of study intervention.
• Must be \> 28 days beyond major surgery, including hepatectomy or joint replacement.
• Prior allogeneic bone marrow transplantation or solid organ transplant.
• Spinal cord compression not definitively treated with surgery and/or radiation.
• Any acute illness including fever (\> 100.4° F or \> 38° C) within 7 days prior to Day 1
• Active systemic bacterial, fungal, or viral infection within 7 days prior to Day 1. Participant cannot have tested positive for COVID-19 within 7 days prior to Day 1.
• Other primary malignancies, except:
  • Adequately treated basal cell or squamous cell carcinoma
  • In situ carcinoma of the cervix or bladder, treated curatively and without evidence of recurrence for at least 2 years prior to the study, or
  • A primary malignancy which has been completely resected and in complete remission for at least 2 years
• Prior grade \> 3 immune-related AEs such as pneumonitis, colitis, hepatitis, nephritis; prior dermatitis and endocrinopathies are allowed provided corticosteroids are no longer required and endocrine-replacement therapy is stable and discontinued from prior therapy.
• Active autoimmune disease not related to prior therapy for primary malignancy that has required systemic therapy in the last 1 year.
• Has received:
  • Radiotherapy within 2 weeks of first administration of MT-302
  • Cytotoxic chemotherapy for treatment of the primary malignancy within 28 days or 5 half-lives, whichever is shorter, of administration of MT-302
  • Immune therapy for primary malignancy (eg, monoclonal antibody therapy, checkpoint inhibitors) within 28 days or 5 half-lives, whichever is shorter of first administration of MT-302
  • Targeted therapies for primary malignancy within 28 days or 5 half-lives, whichever is shorter, of first administration of MT-302
  • Anti-cancer vaccine within 12 weeks of first administration of MT-302
  • COVID-19 mRNA vaccine within 6 weeks of first administration of MT-302
• Has received a live vaccine ≤ 6 weeks prior to first administration of MT-302
• Enrollment in another interventional clinical trial within 28 days or 5 half-lives of the drug, whichever is shorter, of first administration of MT-302

Other illness

• Active infection with human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV).
• History of (noninfectious) pneumonitis/interstitial lung disease that required steroids or has current pneumonitis/interstitial lung disease.
• History of symptomatic congestive heart failure (New York Heart Association classes II-IV) or serious active arrhythmias or other clinically significant cardiac disease within 12 months of enrollment.
• History of an allergic reaction to any of the excipients
• Any other condition that, in the opinion of the Investigator, would make the participant unsuitable for the study or unable to comply with the study requirements.

Lab values

• Toxicity from previous anti-cancer therapy defined as toxicities (other than alopecia, or laboratory values listed above) not yet resolved to NCI CTCAE v5.0 Grade ≤ 1 or baseline. Participants with chronic Grade 2 toxicities (eg, peripheral neuropathy, laboratory values) may be eligible per the discretion of the Investigator and Medical Monitor.
• Has received packed red blood cells or platelet transfusion within 2 weeks prior to first administration of MT-302

Other

• Pregnant or nursing women.
• Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures.

• Adults age ≥ 18 inclusive at the time the Informed Consent Form (ICF) is signed.
• Histologically proven, metastatic or advanced epithelial cancer including the following cancer types:
  • Urothelial
  • Cervical
  • Ovarian epithelial
  • Triple-negative breast
  • HR+/HER2- breast
  • Pancreatic ductal adenocarcinoma
  • Gastric adenocarcinoma
  • Esophageal carcinoma
  • Non-small cell lung
  • Colorectal
• Progressive disease at baseline, refractory or relapsed to standard of care or who have declined standard therapy.
• Measurable disease based on Response Evaluation Criteria in Solid Tumors (RECIST) criteria v 1.1.
• Eastern Cooperative Oncology Group (ECOG) performance status grade of 0 or 1.
• Life expectancy of \> 12 weeks.
• Echocardiogram (ECHO) or multiple gated acquisition scan showing an ejection fraction greater than or equal to 50%.
• Electrocardiogram (ECG) showing no clinically significant abnormality at Screening or showing an average QTc interval \< 450 msec in males and \< 470 msec in females (\< 480 msec for participants with bundle branch block). Either Fridericia's or Bazett's formula may be used to correct the QT interval.
• Oxygen saturation of greater than or equal to 90% on room air measured by pulse oximetry.
• Adequate organ function as defined by laboratory values at Screening.
• Willing and able to provide written informed consent.
• Willing to perform and comply with all study procedures including undergoing study-related biopsies and attending clinic visits as scheduled.
• Men must abstain from sperm donation during study treatment or for 4 months following last dose of study treatment.
• Men and WOCBP must be willing to practice a highly effective method of contraception.